Effects of etidronate on calcification of scales and ribs in the goldfish, Carassius auratus

Effects of etidronate on the calcification of scales and ribs were investigated in goldfish. Daily intraperitoneal injections of etidronate at doses of 1 and 10 mgP/kg body weight for 2 weeks inhibited calcification of ontogenic scales and ribs without affecting the accretion of organic matrices. Removal of some scales induced their regeneration within the two-week period. Their newly formed organic matrix was fully uncalcified in fish treated with 10 mgP/kg, whereas in those treated with 1 mgP/kg, the regenerating scales were only partially calcified. Daily administration of etidronate 10 mgP/kg resulted in an increase of body weight. These results suggested that the inhibitory effect of etidronate on the calcification of osseous tissues in mammals can be expected also on comparable tissues in fishes. An appropriate dose of etidronate that inhibits hard tissue calcification but not affects the body growth in fish seemed to exist between 1 and 10 mgP/kg.